2. In a large nonstick skillet with a heatproof handle, heat the olive oil over medium heat. Add the leftover pasta. Cook, stirring often, for 5 minutes or until the pasta is warm.

3. In a small bowl, beat the eggs, salt, and pepper. Add the egg mixture to the spaghetti. Cook for 2 minutes, shaking the pan occasionally to let the eggs drop through the pasta, until the eggs start to firm at the sides.

4. Transfer the skillet to the oven and bake for 12 minutes or until the frittata is just set. Sprinkle with rosemary and cheese. Serve hot, warm, or at room temperature.